Pullulan, a viscous glucan, is produced and commercialized by culturing a microorganism of species Aureobasidium pullulans on a nutrient culture medium containing saccharide(s), e.g. monosaccharide, lower saccharide, etc., under aerobic conditions. Since pullulan has characteristic properties such as high moldability to form self-supporting membranes, water-solubility, edibility, transparency, oil-resistance, gas-barrier property, gloss and adhesion, is widely used to prepare various molded articles, e.g. granule, rod, film, sheet, tablet, etc.
As in the case of some pharmaceuticals, molded articles having a controlled dissolution/disintegration rate under hydrous conditions are in great demand because of the needs, e.g., to retain a medical efficacy for a prescribed period. Conventional molded articles have characteristic high-solubility and high-disintegrability in water. These natures, however, result in an excessive dissolution/disintegration rate as found in the conventional molded articles, and render the production of gradually disintegrable molded articles very difficult.